Title:Ethics and the Extraterrestrial Environment, by Alan Marshall: http://www.readcube.com/articles/10.1111%2Fj.1468-5930.1993.tb00078.x?r3_referer=wol&tracking_action=preview_click&show_checkout=1&purchase_referrer=onlinelibrary.wiley.com&purchase_site_license=LICENSE_DENIED